Existing consents in spotlight

BY PENNY WARDLE

"As simple as A, B, C" did not apply to the cross-examination of Marlborough District Council hydrologist Val Wadsworth at an Environment Court hearing in Blenheim this week.

Save the Wairau lawyer Mike Hardy-Jones and Fish & Game lawyer Maree Baker quizzed Mr Wadsworth, an expert witness, on how rules for granting water permits under the Wairau Awatere Resource Management Plan meshed with TrustPower's application to divert Wairau River water for hydro-electric power generation.

The council has considered TrustPower's application to draw 40 cumecs of Wairau River water to generate electricity outside the plan's class system, largely because the proposed take exceeded the 15 cumec total of class-B water. It was a complex session, at one point triggering judge Gordon Whiting to ask Mr Wadsworth to use a whiteboard to clarify his explanations.

Mr Wadsworth said conditions attached to TrustPower's consent were probably clearer than rules applying to class B permits.

The class-B requirement that takes be progressively reduced to zero as flow dropped to eight cumecs at Tuamarina for example, had proved unworkable, largely because of the daily or twice-daily flow fluctuations caused by the pulsing effect caused by TrustPower's existing Branch hydro scheme.

Asked about the effect of the TrustPower proposal on existing class-B and C water users in the affected reach, Mr Wadsworth said prior consents on the affected reach of river would need to be considered to ensure flow below the scheme did not fall below the required 15 cumecs.

TrustPower lawyer Christian Whata clarified this issue, saying that both ecological and abstraction requirements must be met.

Generally, the 15 cumec minimum flow below the tailrace would be net of irrigation takes along the affected stretch of river. However, if monitoring at Marchburn picked up that flow had dropped below 15 cumecs, water would need to be released from the Wairau power station into the river.

There were no takes above the Wairau power station, so in effect flow would be wasted in energy terms if it was released from the intake, said Mr Whata.

Mr Wadsworth was asked to provide a table setting out existing class B and C takes on the reach. He understood that about nine cumecs of class-B water might remain unallocated and was not aware of any class-C holders, but believed hill-country storage was being sought.

Ms Baker asked whether there would be less water available to new users, as a result of TrustPower's proposed take. While the answer was yes, in reality there was little land in the Wairau Valley that didn't already have the benefit of a consent, said Mr Wadsworth. There was also some doubling up of consents which would have to be rationalised. Some members of the Wairau Valley Water Enhancement Scheme (WVWES), which planned to piggy-back irrigation on the hydro-electric scheme already had individual consents.

"There will have to be some rationalisation to make sure there's no double-dipping," said Mr Wadsworth. "There will actually be water freed up, possibly a cumec or more." Mr Wadsworth said there was nothing stopping potential new users from applying for non-allocated water because the TrustPower take was being handled outside the class system.

A number of consents had recently been granted to draw water from the affected reach, he said.

New allocations on the south bank included a condition they would relinquish their permit if the hydro scheme went ahead and instead draw from the WVWES canal. At least one permit for a northbank property allowed water to be drawn from the "wedge" of additional water which replenished the river along the length of the scheme, as long as minimum flows at the outlet were not compromised.

"The reality is that this application could safely be made inside the allocation model, could it not?" said Mr Hardy-Jones.

Mr Wadsworth disagreed, saying that there were times when flows in the river might be 50 cumecs at Tuamarina, but only 17 cumecs at the intake. Applying allocation rules in this situation would not sufficiently protect the resource, he said.

The Environment Court is hearing TrustPower's application to build a hydro-electric power scheme on the Wairau River, after a council-appointed panel's decision to grant the company resource consent was appealed.

WATER ALLOCATION

A table in the Wairau Awatere Resource Management Plan determines how Marlborough river water is allocated.

Fifteen cubic metres per second (cumecs) of class B and unlimited volumes of C water are available from the Wairau River.

Class-B takes are available when flow at Tuamarina exceeds eight cumecs.

Class-C water allows two-thirds of flow in excess of 30 cumecs at Tuamarina to be drawn then stored.

The most reliable class-A takes are not available on the Wairau River.

- The Marlborough Express